Noradrenaline-induced pigment aggregating response of melanophores in normal, denervated and reinnervated cichlid skin

The present study examines noradrenaline (NA) effects on melanophore pigment aggregation in normal, denervated and reinnervated teleost skin in vitro. Many axons were present in the melanophore-containing layer of normal skin. One week after a nerve crush lesion the skin was devoid of axons. By 1 month the skin was partly reinnervated. One day after nerve crush NA-sensitivity was markedly increased compared to controls. Sensitivity then approached normality but it remained elevated for at least one month. We conclude that melanophore supersensitivity develops very rapidly upon denervation and then gradually fades away during reinnervation.